Method and apparatus for an ultrasonic emitter system floor audio unit

ABSTRACT

Methods and systems are provided for ultrasonic emitter based floor audio units. An example floor audio unit may comprise one or more ultrasonic emitters and may be placed on or near a floor. The floor audio unit may generate audio output that comprises ultrasonic signals, and may emit the ultrasonic signals using the one or more ultrasonic emitters, where the one or more ultrasonic emitters may be configured to emit the ultrasonic signals upward. Further, directionality of emission of the ultrasonic signals is based on a position of a listener and/or a location of the listener&#39;s head relative to the enclosure of the floor audio unit. The ultrasonic signals and/or the positioning of the one or more ultrasonic emitters may be adjusted based on the position of the listener and/or the location of the listener&#39;s head to optimize the directionality of emission of the ultrasonic signals. The position of the listener and/or the location of the listener&#39;s head may be determined in real-time, such as using sensory information.

CLAIM OF PRIORITY

This patent application claims priority to and benefit from the U.S.Provisional Patent Application Ser. No. 61/907,797, filed Nov. 22, 2013.The above identified provisional patent application is herebyincorporated herein by reference in its entirety.

INCORPORATION BY REFERENCE

This patent application makes references to:

-   U.S. Pat. No. 6,577,738 titled “Parametric virtual speaker and    surround-sound system;”-   U.S. Pat. No. 7,298,853 titled “Parametric virtual speaker and    surround-sound system;” and-   U.S. Pat. No. 7,596,229 titled “Parametric audio system for    operation in a saturated air medium.

Each of the above identified patents is hereby incorporated herein byreference in its entirety.

TECHNICAL FIELD

Aspects of the present application relate to audio systems, particularlysystems that may generate directional sound utilizing ultrasonicemitters. More specifically, various implementations in accordance withthe present disclosure relate to systems and methods for ultrasonicemitter system floor audio units.

BACKGROUND

Limitations and disadvantages of conventional approaches to audio outputdevices, particularly those providing ultrasonic emissions, will becomeapparent to one of skill in the art, through comparison of such systemswith some aspects of the present disclosure as set forth in theremainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE DISCLOSURE

Systems and methods are provided for ultrasonic emitter system flooraudio units, substantially as shown in and/or described in connectionwith at least one of the figures, as set forth more completely in theclaims.

These and other advantages, aspects and novel features of the presentdisclosure, as well as details of an illustrated embodiment thereof,will be more fully understood from the following description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example ultrasonic system that is operable togenerate ultrasonic signals, in accordance with an example embodiment ofthe present disclosure.

FIG. 2 illustrates an example circuit for an ultrasonic device that isoperable to generate ultrasonic signals, in accordance with an exampleembodiment of the present disclosure.

FIG. 3 illustrates an example system that utilizes an ultrasonic emittercomprising a film with a conductive layer to generate ultrasonic signalsin an electrostatic arrangement, in accordance with an exampleembodiment of the present disclosure.

FIG. 4 illustrates an example configuration of an ultrasonic emittercomprising a film with a conductive layer to generate ultrasonic signalsin an electrostatic arrangement, in accordance with an exampleembodiment of the present disclosure.

FIG. 5A illustrates an example transformer coupled to an ultrasonicemitter that utilizes a film with a conductive layer with a conductivelayer, in accordance with an example embodiment of the presentdisclosure.

FIG. 5B illustrates an example self-bias circuit for use in ultrasonicemitters, in accordance with various example embodiments of the presentdisclosure.

FIG. 6A illustrates an example ultrasonic emitter system floor audiounit, in accordance with an example embodiment of the presentdisclosure.

FIG. 6B illustrates an example use scenario of a listener standing atthe optimal standing position in front an ultrasonic emitter systemfloor audio unit that projects sound upwards, in accordance with anexample embodiment of the present disclosure.

FIG. 6C illustrates an example ultrasonic emitter system floor audiounit comprising integrated sensors, in accordance with an exampleembodiment of the present disclosure.

FIG. 6D illustrates an example ultrasonic emitter system floor audiounit comprising an integrated camera, in accordance with an exampleembodiment of the present disclosure.

FIG. 7 is a flow chart illustrating an example process for generatinghypersound audio from an ultrasonic emitter system floor audio unit, inaccordance with various example embodiments of the present disclosure.

FIG. 8 is a flow chart illustrating an example process for generatinghypersound audio from an ultrasonic emitter system floor audio unit, inaccordance with various example embodiments of the present disclosure.

FIG. 9 is a flow chart illustrating an example process for hypersoundaudio from an ultrasonic emitter system floor audio unit, in accordancewith various example embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

As utilized herein the terms “circuits” and “circuitry” refer tophysical electronic components (“hardware”) and any software and/orfirmware (“code”) which may configure the hardware, be executed by thehardware, and or otherwise be associated with the hardware. As usedherein, for example, a particular processor and memory may comprise afirst “circuit” when executing a first plurality of lines of code andmay comprise a second “circuit” when executing a second plurality oflines of code. As utilized herein, “and/or” means any one or more of theitems in the list joined by “and/or”. As an example, “x and/or y” meansany element of the three-element set {(x), (y), (x, y)}. In other words,“x and/or y” means “one or both of x and y.” As another example, “x, y,and/or z” means any element of the seven-element set {(x), (y), (z), (x,y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and/or z” means“one or more of x, y and z.” As utilized herein, the terms “block” and“module” refer to functions than can be performed by one or morecircuits. As utilized herein, the term “example” means serving as anon-limiting example, instance, or illustration. As utilized herein, theterms “for example” and “e.g.,” introduce a list of one or morenon-limiting examples, instances, or illustrations. As utilized herein,circuitry is “operable” to perform a function whenever the circuitrycomprises the necessary hardware and code (if any is necessary) toperform the function, regardless of whether performance of the functionis disabled or not enabled (e.g., by a user-configurable setting,factory trim, etc.).

FIG. 1 illustrates an example ultrasonic system that is operable togenerate ultrasonic signals, in accordance with an example embodiment ofthe present disclosure. Shown in FIG. 1 is an ultrasonic system 100,which may comprise an audio source 102 and pair of ultrasonic emitters104 a and 104 b.

The audio source 102 may comprise suitable circuitry operable toreceive, generate, and/or process audio signals for output to one ormore conventional speakers and/or directional ultrasonic emitters. Forexample, in the implementation shown in FIG. 1, the audio source 102 maybe operable to receive, generate, and/or process audio signals foroutput to the ultrasonic emitters 104 a and 104 b, which may be coupledto the audio source 102 via links 103 a and 103 b. For illustration, thesystem is assumed to be a HyperSound System (HSS) that uses ultrasonicemitters for projecting directional ultrasonic signals as described, forexample, in U.S. Pat. Nos. 7,298,853, 6,577,738, and 7,596,229 (all ofwhich are hereby incorporated herein by reference in their entirety) andalso in www.parametricsound.com/technology.php. Nonetheless, aspects ofthe present disclosure may be used with other technology for generatingdirectional ultrasonic signals.

The audio source 102 may be, for example, a dedicated audioreceiver/processor, a multi-function set-top-box (e.g., a cabletelevision set-top-box or Direct Broadcast Satellite set-top box), acomputer (e.g., Windows, MAC, or Linux based) with sound processing andoutput capabilities, or the like.

Each of the links 103 a and 103 b may be a wired, wireless, and/oroptical link. Links 103 a, 103 b may carry an electrical and/or opticalrepresentation of an audio-band signal.

Each of the ultrasonic emitters 104 a and 104 b may be operable toreceive an audio-band signal from its respective one of links 103 a and103 b and convert the audio-band to ultrasonic waves transmitted in ahighly-focused air beam (shown as air beams 106 a and 106 b).Alternatively, audio source 102 may comprise suitable circuitry forproviding ultrasonic modulation, and links 103 a and 103 b may carry anelectrical and/or optical representation of an ultrasonic signal. Thepropagation of the ultrasonic signal in air may effectively demodulatethe ultrasonic signals with respect to the listener; thus, an activedemodulation device may not be required. The corresponding demodulatedaudio-band signal may be audible to the listener 110 that is within theair-beams, namely 106 a and 106 b. The corresponding demodulatedaudio-band signals may be greatly attenuated to the listener 112. Theemitters 104 a and 104 b may be mounted in any desired location. Forexample, they may be mounted to either side of a television asconventional left and right channels speakers are typically mounted. Asanother example, the speakers may be mounted in an apparatus that placesthem close to the listeners ears (e.g., mounted to a chair that thelistener sits in) to achieve sound quality similar to headphones butwithout having headphones actually touching the listeners head.

Aspects of this disclosure improve the ability of the system shown inFIG. 1 to create a three-dimensional sound effect whereby, although theaudio-band signal is emitted from only the two emitters 104 a and 104 b,the listener 110 perceives various sounds in the audio as emanating fromvarious locations in the 3D space around him/her (i.e., virtual surroundsound).

In accordance with some embodiments of the disclosure, the exemplarysystem that is illustrated in FIG. 1 may also be operable to generate athree-dimensional sound and may comprise one or more ultrasonic emittersthat comprise glass, aluminum, graphene, ferro-fluid, and/or othermaterial, which may be operable to generate a ultrasonic output.

FIG. 2 illustrates an example circuit for an ultrasonic device that isoperable to generate ultrasonic signals, in accordance with an exampleembodiment of the present disclosure. Shown in FIG. 2 is an ultrasonicdevice 200.

The ultrasonic device 200 may comprise suitable circuitry for generatingand/or outputting ultrasonic signals. For example, as shown in theimplementation depicted in FIG. 2, the ultrasonic device 200 maycomprise an audio source 202, processing circuits 204 a and 204 b,ultrasonic generators/emitters 208 a and 208 b, an audio processingcircuit 210, and speaker 212.

The audio source 202 may comprise, for example, memory for storing audiofiles and circuitry for reading the audio files and generatingelectrical and/or optical audio-band signals. The audio source 202 maycomprise, for example, circuitry for receiving and processing audiosignals (e.g., circuitry for demodulating, decoding, etc. to recover anaudio band signal from a modulated carrier) that were transmitted over awired, wireless, or optical link. The audio source 202 may, for example,reside in the receiver 102 of FIG. 1. The audio source 202 outputs aleft channel audio signal 203 a and a right channel audio signal 203 b,each of which may be an optical and/or electrical audio-band signal.

The processing circuits 204 a and 204 b may be operable to process thesignal 203 (e.g., perform frequency-dependent amplitude, frequency,and/or phase adjustment) to generate signals 205 a and 205 b. Ascompared to driving the ultrasonic emitters (either directly, or viacircuits 206 a and 206 b) with the signals 203 a and 203 b, the signals205 a and 205 b may result in a three-dimensional sound effect that theuser perceives as more realistic/natural. In this regard, a problem thatarises with the ultrasonic emitters is that the power of the sound inthe ultrasonic sound column does not diminish as a function of distancein the same way that sound normally does in free space (the path loss ofan audio signal in free space is (4*πd/λ)² where d is the distance fromtransmitter to receiver and λ is the wavelength of the signal).Consequently, the sound may be perceived as unnatural to the listener.Accordingly, the circuits 204 a and 204 b may be configured to apply atransfer function that may mimic the free space propagation loss thatthe ultrasonic signals would experience if propagating in free space—asis the manner in which the listener is used to hearing such sounds. Toapply such processing, the circuits 204 a and 204 b may first determinethe distance from the emitters 208 a and 208 b to the listener. Thisdistance may be determined in any suitable way. In an exampleimplementation, the distance may be determined by infrared, laser, orother distance measuring sensors integrated into the emitters 208 a and208 b and/or a receiver, a set-top box, etc. that houses the circuits202, 204, and 210. In an example implementation, the distance may beinput by a user or installer of the system (e.g., via a graphical userinterface). Alternatively, the transfer function may represent thefrequency response of the emitter.

The ultrasonic generators/emitters 208 a and 208 b are operable toreceive the electrical and/or optical audio band signal 207 a and 207 band convert them to ultrasonic beams, as described above with respect toFIG. 1, for example. Each of the ultrasonic generators/emitters 208 aand 208 b may comprise a glass, aluminum, ferro-fluid, graphene and/orother type of emitter, which is operable to generate ultrasonic signals.Alternatively, circuitry 204 a and 204 b may comprise ultrasonicmodulation and links 205 a and 205 b may carry an electrical and/oroptical representation of an ultrasonic signal.

The system of FIG. 2 also comprises a conventional speaker 212, for useas center channel speaker, which outputs sound wave 214 corresponding tocenter channel audio. For example, the center channel audio frequenciesmay be below 250-300 Hz. The sound wave 214 experiences free space pathloss as non-directional audio waves conventionally do.

The different propagation characteristics of the ultrasonic beams 106and the sound wave 214, there may cause an unnatural phase and/or timedelay between the left and right channel audio arriving via emitters 208and the center channel audio arriving via speaker 212. Accordingly, thecircuitry 210, 204 a, and 204 b may be operable to process the left,right, and center channel audio such that the center channel arrives atthe proper time and/or phase relative to the left and right channels, aswould be the case if all three channels were transmitted viaconventional speakers.

FIG. 3 illustrates an example system that utilizes an ultrasonic emittercomprising a film with a conductive layer to generate ultrasonic signalsin an electrostatic arrangement, in accordance with an exampleembodiment of the present disclosure. Shown in FIG. 3 is an ultrasonicemitter 300 which may utilize a film to generate ultrasonic signals.

The ultrasonic emitter 300 may comprise a conductive backplate 302, afaceplate, and a protective screen 326. The reference numerals 314 a-314i are utilized to define the perimeter of the chamber 316. Theultrasonic emitter 300 described herein may also be referred to as anelectrostatic transducer. U.S. Pat. Nos. 4,246,449 and 4,081,626disclose example electrostatic transducers.

The backplate 302 may comprise suitably rigid material that may beoperable to provide a stable support for the emitter structure 300. Thebackplate 302 may comprise an electrically conductive material. In thisregard, the backplate 302 may be coupled to a first electrical lead thatmay be utilized to bias the ultrasonic emitter 300. In accordance withan embodiment of the disclosure, the backplate 302 may comprise analuminum backplate.

The backplate 302 may comprise a plurality of cavities 308. The cavities308 may also be referred to as grooves or channels. Notwithstanding, thecavities 308 may be etched or otherwise placed within a front surface ofthe backplate 302. The peaks 314 a and 314 b resulting from cavities 308may be utilized to support the faceplate. The enclosed structure formedby the peaks 314 a, 314 b, the ridges 314 c, 314 d, 314 e, the bottom ofthe cavities 314 f, 314 g, 314 h, 314 i and the non-conducting material312 comprises a chamber 316.

The faceplate may comprise a film with a conductive layer or diaphragmthat resonates to generate the ultrasonic signal from the ultrasonicemitter 300. The film or diaphragm may comprise, for example, a Mylar orKapton electrostatic film, Polypropylene film, Polyvinylidene Fluoride(PVDF) film and/or other film or diaphragm suitable for generatingultrasonic signals. In various example embodiments of the disclosure,the faceplate comprising the film or diaphragm may comprise an outerconductive material 310 and a non-conductive material 312. In theexample ultrasonic emitter 300, the resonating faceplate 310 comprisingthe film may be operable to function as a diaphragm that is displaced inorder to propagate the corresponding ultrasonic waves. The faceplatecomprising the film diaphragm may be coupled to a second electrical lead(via the conductive material 310) that may be utilized to bias theultrasonic emitter 300.

The non-conductive material 312 may isolate the conductive material 310from the conductive backplate 302. In this regard, the non-conductivematerial 312 may prevent an electrical short from occurring between thefaceplate 310 comprising the film and the backplate 302.

Although, the conductive material 310 and the non-conductive material312 are illustrated separately, the disclosure is not limited in thisway. The conductive material 310 and the non-conductive material 312together may form an inseparable thin film. The geometry and dimensionof the ultrasonic emitter 300 and the volume of the chamber 316 maycomprise example factors that may affect performance of the emitter. Forexample, the greater the volume of the chamber 316, the lower theresonant frequency. The number of ridges within the chamber 316 may alsoaffect performance of the emitter. Although three ridges, namely, 314 c,314 d, 314 e are shown between the peaks 314 a, 314 b, the disclosure isnot limited in this regard. Accordingly, there may be less than 3 ridgesor greater than 3 ridges between the peaks 314 a, 314 b. In someembodiments of the disclosure, there may be 3-5 ridges between the peaks314 a, 314 b. Additionally, the angle 320 may be 90 degrees to provideoptimal reflection of sonic or ultrasonic waves. An angle ofapproximately 90 degrees and an optimal number of ridges between thepeaks 314 a, 314 b may cause an increase in the resonant frequency ofthe ultrasonic emitter 300, which in turn causes an increase in theultrasonic output of the emitter.

The protective screen 326 may comprise a suitable material that mayprotect the ultrasonic emitter 300 or, for example, in particular, thefaceplate 310 from damage. The material that is utilized for theprotective screen 326 may be selected so that it may enhance theultrasonic output. In an example embodiment of the disclosure, theprotective screen 326 may comprise a plastic screen. In this regard, theplastic screen may, for example, function as an impedance matchingelement that increases the ultrasonic output. In an example embodimentof the disclosure, the plastic screen may double the ultrasonic outputpower. The protective screen 326 may be cosmetic and may also benecessary for standards approval such as Underwriters Laboratory (UL)approval.

FIG. 4 illustrates an example configuration of an ultrasonic emittercomprising a film with a conductive layer to generate ultrasonic signalsin an electrostatic arrangement, in accordance with an exampleembodiment of the present disclosure. Shown in FIG. 4 is an ultrasonicemitter 400 that utilizes a film with a conductive layer to generateultrasonic signals.

The ultrasonic emitter 400 may be substantially similar to theultrasonic emitter 300, which is shown and described with respect to,for example, FIG. 3. The ultrasonic emitter 400 may comprise, forexample, a conductive backplate 402, and a faceplate. The ultrasonicemitter 400 may also comprise a plurality of ridges such as a ridge 414e, a chamber 416, and a plurality of cavities 408 on the backplate 402.The structure of the ultrasonic emitter 400 may be substantially similarto the structure of the emitter 300, which is shown and described withrespect to, for example, FIG. 3. Accordingly, the backplate 402, thepeaks 414 a, 414 b, the ridge 414 e, the faceplate, the chamber 416, andthe plurality of cavities 408 may be similar to the correspondingcomponents, namely, the backplate 302, the peaks 314 a, 314 b, the ridge314 e, the faceplate, the chamber 316, and the plurality of cavities308, respectively, which are shown and described with respect to, forexample, FIG. 3.

The faceplate may comprise a film with a conductive layer or diaphragmthat resonates to generate the ultrasonic signal from the ultrasonicemitter 400. In various example embodiments of the disclosure, thefaceplate comprising the film or diaphragm may comprise a conductivematerial 410 and a non-conductive material 412.

In various implementations, the design and/or construction of theultrasonic emitter 400 may be adjusted based on performance criteria orparameters. In this regard, in general, the greater the surface area ofthe faceplate, which comprises the film, the greater the output may befor the same amount of power. Additionally, the greater the volume ofthe faceplate or film for the ultrasonic emitter 400 and/or the greaterthe volume of the chamber 416 for the ultrasonic emitter 400, the lowerthe resonant frequency.

Various example dimensions are illustrated in FIG. 4, which may beutilized by the ultrasonic emitter 400. In this regard, the thin designof the ultrasonic emitter 400 provides greater flexibility.

For example, the dimension D may represent the difference between theheight of the peak 414 b and the height of the ridge 414 e. In anexample embodiment of the disclosure, dimension D may be approximately13 microns or about 0.0005 inch. The ultrasonic emitter 400 may bedesigned such that when the faceplate and the non-conductive material412 resonates, which are supported by the peaks 414 a, 414 b, thefaceplate and the non-conductive material 412 does not touch the ridgessuch as the ridge 414 e, which are within the chamber 416.

The dimension C may represent the distance between the supports or peaks414 a and 414 b. In an example embodiment of the disclosure, thedimension C may be approximately 0.12 inch.

The dimensions A, B, and C may be selected so that they are afunctionality of the wavelength, λ. In accordance with some embodimentsof the disclosure, the dimensions A, B, C may be chosen so as to achievea resonant frequency that is approximately equivalent to the naturalresonant frequency of the film that is utilized for the faceplate, whichcomprises a film or diaphragm.

The thickness of the faceplate, which comprises a film or diaphragm, maybe related to the wavelength of the carrier frequency, f_(c). Thethickness of the faceplate comprising the film or diaphragm may beselected so that it provides suitable headroom for the bias voltage. Forexample, a thickness with ½ mil (0.0005 inch) may provide betterheadroom voltage comparing to a thickness with ¼ mil.

The number of ridges between the peaks 414 a, 414 b, which support thefaceplate, may affect the resonant frequency of the ultrasonic emitter400. In accordance with various embodiments of the disclosure, anoptimal number of ridges between the peaks 414 a, 414 b increases theresonant frequency of the ultrasonic emitter 400. The resultant increasein the resonant frequency of the ultrasonic emitter 400 causes anincrease in the ultrasonic output of the emitter.

FIG. 5A illustrates an example transformer coupled to an ultrasonicemitter that utilizes a film with a conductive layer with a conductivelayer, in accordance with an example embodiment of the presentdisclosure. Shown in FIG. 5A is circuitry 500 and an example ultrasonicemitter 501.

The circuitry 500 comprises an amplifier 532, a transformer 534, and aself-bias circuit 536. The ultrasonic emitter 501 may comprise aconductive backplate 502 and a faceplate. The faceplate may comprise,for example, a conductive material 510 and a non-conductive material512.

Although, the conductive material 510 and non-conductive material 512are illustrated as separate elements, the disclosure is not limited inthis way. For example, the conductive material 510 and thenon-conductive material 512, such that, for example, the conductivematerial 510 and the non-conductive material 512 together comprise aninseparable thin film.

The ultrasonic emitter (transducer) 501 may be substantially similar tothe ultrasonic emitter 300, which is shown and described with respectto, for example, FIG. 3. Accordingly, the backplate 502 and thefaceplate may be similar to the corresponding components, namely, thebackplate 302 and the faceplate, respectively, which are shown anddescribed with respect to, for example, FIG. 3.

The amplifier 532 may comprise, for example, a class D switchingamplifier. In an example embodiment of the disclosure, the amplifier 532and/or the transformer 534 may, for example, reside in the audioreceiver/processor 102 of FIG. 1, or reside in the processing circuit204 a or 204 b of FIG. 2.

The transformer 534 may comprise primary and secondary windings. Theprimary windings of the transformer 534 may be electrically coupled tothe amplifier 532. The secondary windings of the transformer 534 may beelectrically coupled to the self-bias circuit 536. The self-bias circuit536 may in turn be coupled to the ultrasonic emitter 501. In thisregard, the transformer 534 may receive an input signal V_(P) from theamplifier 532 via the primary windings of the transformer 534. The inputsignal V_(P) may be coupled with a DC bias produced by, for example, theself-bias circuit 536, such that, for example, and an output signalV_(S) from the secondary winding of the transformer 534 may comprise anultrasonic signal combined with a biasing voltage of, for example,approximately 100-300 volts DC. A first output of the self-bias circuit536 may be electrically coupled to the conductive material 510 of theultrasonic emitter 501, and a second output of the self-bias circuit 536may be electrically coupled to the backplate 502 of the ultrasonicemitter 501. In such instances, the output signal V_(S) may be appliedbetween the conductive material 510 and the backplate 502.

FIG. 5B illustrates an example self-bias circuit for use in ultrasonicemitters, in accordance with various example embodiments of the presentdisclosure. Shown in FIG. 5B is an example self-bias circuit 550. Theself-bias circuit 550 is an example embodiment of the self bias circuit536, which is shown and described with respect to FIG. 5A.

A first output of the self-bias circuit 536 may be electrically coupledto the conductive material 510 (FIG. 5A) of the ultrasonic emitter 501,and a second output of the self-bias circuit 536 may be electricallycoupled to the backplate 502 (FIG. 5A) of the ultrasonic emitter 501(FIG. 5A). In such instances, the output signal V_(S) may be appliedbetween the conductive material 510 (FIG. 5A) and the backplate 502(FIG. 5A).

FIG. 6A illustrates an example ultrasonic emitter system floor audiounit, in accordance with an example implementation of the presentdisclosure. Shown in FIG. 6A is an ultrasonic emitter system floor audiounit 600.

The ultrasonic emitter system floor audio unit 600 may comprise anenclosure 602, a pair of ultrasonic generators/emitters 604 a and 604 b,a sub-woofer 606, a controller 608, and a protective material orcomponent 610. The enclosure 602 may function as a housing that encasesand protects the components of the ultrasonic emitter system floor audiounit 600. The enclosure 602 may comprise a rigid material such as aplastic, metal and/or a composite material. The dimensions of theenclosure 602 may be kept at a minimum so as to enable the ultrasonicemitter system floor audio unit 600 to be utilized in many applications,especially applications in which space may be a premium. For example,the height of the enclosure 602 may be minimized so that the enclosure602 has a very low profile. The enclosure 602 may be placed on a flooror near to a floor, for example, in or proximate to a booth or a kiosk(or otherwise be integrated into a booth or kiosk at or near the floor).Further, the ultrasonic emitter system floor audio unit 600 (and variouscomponents thereof) may be configurable to account for such placement,such as to ensure that output signals are projected based on thatplacement and/or positioning of listeners' relative to the ultrasonicemitter system floor audio unit 600.

The enclosure 602 may comprise a mounting mechanism (not shown) for theultrasonic generators/emitters 604 a and 604 b, which enables theultrasonic generators/emitters 604 a and 604 b to be angled or tilted inone or more planes so that ultrasonic beams may be directed towards ahead of a listener. The dotted arrows illustrates an example plane inwhich the ultrasonic generators/emitters 604 a and 604 b may be angledor tilted to project output (e.g., ultrasonic beams or hypersound audio)from the floor up towards a head of a listener.

The ultrasonic generators/emitters 604 a and 604 b may be operable toreceive electrical and/or optical audio band signals and convert them toultrasonic beams, as described above. For example, the ultrasonicgenerators/emitters 604 a and 604 b may be substantially similar to theultrasonic generators/emitters 208 a and 208 b, which are illustrated inand described above with respect to FIG. 2, for example. Each of theultrasonic generators/emitters 604 a and 604 b may comprise a glass,aluminum, ferro-fluid, graphene and/or other type of emitter, which isoperable to generate ultrasonic signals.

In an example implementation, the ultrasonic generators/emitters 604 aand 604 b may be affixed to motorized mounts within the enclosure 602.These motorized mounts may be used, for example, in order to adjust theangle of the ultrasonic generators/emitters 604 a and 604 b so that theymay optimally direct and project the audio (e.g., 3D hypersound audio)towards the ear of the listener.

The sub-woofer 606 may be operable to receive audio band signals fromthe controller 608 and convert them to low frequency sub-woofer audio.The sub-woofer 606 may be encased in the enclosure of the ultrasonicemitter system floor audio unit 600.

The controller 608 may comprise suitable circuitry for enabling theultrasonic emitter system floor audio unit 600 to receive power, andelectrically and/or optically received audio band signals and convertthem to ultrasonic beams. The controller 608 may also comprise anamplifier that may be utilized to amplify the received audio bandsignals and generate corresponding audio signals from the sub-woofer606. The controller 608 may also be operable to control other functionsand/or operations in (or of) the ultrasonic emitter system floor audiounit 600. For example, the controller 608 may be operable to controlmovement of the mounting mechanism for the ultrasonicgenerators/emitters 604 a and 604 b, which enables the ultrasonicgenerators/emitters 604 a and 604 b to be angled or tilted. In thisregard, the controller 608 may tilt or angle the ultrasonicgenerators/emitters 604 a and 604 b so that ultrasonic beams may bedirected upwards from the floor towards a head of a listener that isstanding in front of the ultrasonic emitter system floor audio unit 600.Alternatively, the controller may apply or modify beamforming to steeroutput of the ultrasonic generators/emitters 604 a and 604 b so thatultrasonic beams may be directed upwards from the floor towards a headof listener that is standing in front of the ultrasonic emitter systemfloor audio unit 600.

The protective material or component 610 may comprise suitable materialthat may be operable to protect at least the ultrasonicgenerators/emitters 604 a and 604 b and at the same time enable thecorresponding ultrasonic signals to be emitted from the ultrasonicgenerators/emitters 604 a and 604 b. In an example implementation, theprotective material or component 610 may comprise a protective cloth orsheath. In another example implementation, the protective material orcomponent 610 may comprise a protective grill that is placed in front ofthe ultrasonic generators/emitters 604 a and 604 b, and optionally, infront of the sub-woofer 606. In some implementations, the protectivegrill may be placed so that it covers the entire front of the enclosure602 facing the ultrasonic generators/emitters 604 a and 604 b.

In various example implementations, the ultrasonic emitter system flooraudio unit 600 may be located on or near to a floor (e.g., at aresidence, in or proximate to a retail display or booth, kiosk, etc.).The ultrasonic generators/emitters 604 a and 604 b in emitter systemfloor audio unit 600 may be adjusted or tilted so that they projecthypersound (ultrasonic beams) upwards to create a sweet spot or optimalposition of 3D audio a few feet out towards a listener that may bestanding in front of the ultrasonic emitter system floor audio unit 600.In other words, the ultrasonic emitter system floor audio unit 600 maybe operable to project ultrasonic beams upwards from the ground in orderto create a 3D audio environment for a listener standing in the rightposition in front of the ultrasonic emitter system floor audio unit 600.In doing so, the ultrasonic emitter system floor audio unit 600 and/orvarious components thereof may be controlled or adjusted to account forthe placement of the enclosure 602 on or near the floor and/or thepositioning of the listeners' (e.g., generally being upward from theenclosure 602, and/or the particular positioning of each listener).

In an example implementation, floor audio units (e.g., the floor audiounit 600) may be designed and/or constructed such that they may beintegrated directly into floor (rather than being built as stand-alonedevices or components). Alternatively, the floor audio units may bedesigned and/or constructed such that they may be integrated into flator very then objects (e.g., floor mats) so that they may be laid (aspart of the objects into which they are integrated) on the floor thusallowing users to walk or step over them. To enable suchimplementations, speakers (particularly the ultrasonicgenerators/emitters) may be designed and/or built to be thin as to allowintegration into the floors and/or into thin objects laid on the floors,while still providing any required directional emissions (e.g., off thevertical, as they likely would be positioned flat on the floors) byother suitable means or techniques.

FIG. 6B illustrates an example use scenario of a listener standing atthe optimal standing position in front an ultrasonic emitter systemfloor audio unit that projects sound upwards, in accordance with anexample implementation of the present disclosure. Shown in FIG. 6B is aparticular space 620, in which the ultrasonic emitter system floor audiounit 600 (as described in FIG. 6A) may be placed, particularly on thefloor or near it. Also shown in FIG. 6B are a floor mat 622 and alistener 624. The floor mat 622 comprises an optimal standing positionmarker 626.

The ultrasonic emitter system floor audio unit 600 comprises theenclosure 602, the ultrasonic generators/emitters 604 a and 604 b, thesub-woofer 606, the controller 608, and the protective material orcomponent 610. The enclosure 602, the ultrasonic generators/emitters 604a and 604 b, the sub-woofer 606, the controller 608, and the protectivematerial or component 610 are described with respect to FIG. 6A, forexample.

The floor mat 622 may be placed or painted on the floor and comprisesthe optimal standing position marker 626. The optimal standing positionmarker 626 comprises a visible marking that functions as a visual aidthat may be utilized by the listener 624 to align themselves with theultrasonic generators/emitters 604 a and 604 b for optimal reception ofthe 3D hypersound audio that is projected upwards from floor. Thelistener 624 may stand within the region defined by the optimal standingposition marker 626 in order to optimally listen to the upwardlyprojecting 3D hypersound audio that is generated from the ultrasonicgenerators/emitters 604 a and 604 b.

Although a single marker is illustrated, the disclosure is not limitedin this regard. Accordingly, a plurality of markers may be utilized. Forexample, two markers may be utilized, and the listener 624 may standwith each foot on one of the markers.

In the example use scenario shown in FIG. 6B, the optimal positioningmay be pre-determined, thus allowing determining the optimal standingposition marker 626. Nonetheless, in other implementations, rather thansimply pre-determining a particular optimal standing positioning, thepositioning of the would-be listener may be determined, and thegeneration and/or outputting functions (or related components) may beadjusted to account for that positioning such as to ensure optimalexperience at the determined position. Further, in some implementations,ultrasonic emitter system floor audio units in accordance with thepresent disclosure may be configured to concurrently optimize listeningexperience of multiple listeners, such as by determining positioning ofeach listener, and generating output beams that are particularlyadjusted and/or optimized for each listener.

FIG. 6C illustrates an example ultrasonic emitter system floor audiounit comprising integrated sensors, in accordance with an exampleimplementation of the present disclosure. Shown in FIG. 6C is anultrasonic emitter system floor audio unit 640.

The ultrasonic emitter system floor audio unit 640 may comprise anenclosure 602, ultrasonic generators/emitters 604 a and 604 b, asub-woofer 606, a controller 608, a protective material or component610, and a plurality of sensors S1, S2, S3, S4, S5, S6, and S7.

The ultrasonic emitter system floor audio unit 640 comprising theenclosure 602, the ultrasonic generators/emitters 604 a and 604 b, thesub-woofer 606, the controller 608, and the protective material orcomponent 610 are illustrated in and described with respect to FIG. 6A,for example.

The enclosure 602 may also function as a housing that encases andprotects the components of the ultrasonic emitter system floor audiounit 640. In this regard, the enclosure 602 may also serve as a supportfor the plurality of sensors S1, S2, S3, S4, S5, S6, and S7. In thisregard, the sensors S1, S2, S3, S4, S5, S6, and S7 may be mounted on theface and/or on the top of the enclosure 602. Sensors that are mounted onthe top of the enclosure 602 may be placed towards the front of theenclosure 602.

Each of the plurality of sensors S1, S2, S3, S4, S5, S6, and S7 maycomprise suitable logic, circuitry, interfaces and/or code that may beoperable to emit electromagnetic signals and/or sonic signals that maybe utilized to determine the height of the listener. In this regard, thesensors S1, S2, S3, S4, S5, S6, and S7 may comprise transducers that maybe utilized to determine the height of the listener. Based on the heightof the listener, the ultrasonic generators/emitters 604 a and 604 b maybe angled or tilted so that they may direct and project the 3Dhypersound audio towards the ear of the listener. In this regard, thelistener 624 may optimally listen to the upwardly projecting 3Dhypersound audio that is generated from the ultrasonicgenerators/emitters 604 a and 604 b.

The controller 608 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to control operation of the sensors S1,S2, S3, S4, S5, S6, and S7. In this regard, the controller 608 may beoperable to configure the sensors to transmit and/or receive signalsthat may be utilized to determine the height of the listener. Thecontroller 608 may determine the height of the listener based on, forexample, changes in frequency (Doppler), and/or phase of the transmittedand received signals. The controller 608 may be operable to control theone or more motorized mounts in the enclosure 602 in order to optimallyadjust the angle of the ultrasonic generators/emitters 604 a and 604 bso that they may direct and project the 3D hypersound audio towards thehead and ears of the listener based on the determined height of thelistener.

In accordance with an example implementation, one or more the sensorsS1, S2, S3, S4, S5, S6, and S7 may comprise a directional microphonethat may be utilized to capture audio from the listener. In an exampleimplementation, pre-recorded audio instructions may be played requestingthe listener to utter a random or predefined phrase or sound. Thecontroller 608 may adjust and/or process the corresponding sound that isreceived from the listener. Based on the processing, the controller 608may determine the location of the mouth of the listener. Alternatively(or additionally), the audio requested from the listener might be anindication or utterance of the listener's height. In any event, thecontroller 608 may be operable to control the one or more motorizedmounts in the enclosure 602 in order to optimally adjust the angle ofthe ultrasonic generators/emitters 604 a and 604 b so that they maydirect and project the 3D hypersound audio towards the ears of thelistener based on the determined location of the mouth of the listeneror based on the height of the individual. The ultrasonicgenerators/emitters 604 a and 604 b may then project 3D hypersound audiofrom the floor up towards the head of the listener.

FIG. 6D illustrates an example ultrasonic emitter system floor audiounit comprising an integrated camera, in accordance with an exampleimplementation of the present disclosure. Shown to FIG. 6D is anultrasonic emitter system floor audio unit 660.

The ultrasonic emitter system floor audio unit 660 may comprise anenclosure 602, ultrasonic generators/emitters 604 a and 604 b, asub-woofer 606, a controller 608, a protective material or component610, and an integrated camera 612. The ultrasonic emitter system flooraudio unit 660 may comprise the sensors S1, S2, S5, which may or may notbe optional components. In an example implementation, one of the sensorsS1, S2, S5 may comprise a proximity sensor and another may comprise amicrophone.

The ultrasonic emitter system floor audio unit 660 comprising theenclosure 602, the ultrasonic generators/emitters 604 a and 604 b, thesub-woofer 606, the controller 608, and the protective material orcomponent 610 are illustrated in and described with respect to FIG. 6A,for example. The sensors S1, S2, S5 are illustrated in and describedwith respect to FIG. 6C, for example.

The enclosure 602 may also function as a housing that encases andprotects the components of the ultrasonic emitter system floor audiounit 660. In this regard, the enclosure 602 may also comprise anintegrated camera 612. The integrated camera 612 may be mounted on theface or top of the enclosure 602 where it may be able to capture anddetect the face or head of the listener.

In an example implementation, the sensors S1, S5 may comprise proximitysensors and the sensor S2 may comprise a microphone. The proximitysensors S1, S5 may each comprise a transducer that may be utilized todetermine the height of the listener. Based on the height of thelistener, the angle of ultrasonic generators/emitters 604 a and 604 bmay be adjusted so that they may direct and project the 3D hypersoundaudio up towards the ears of the listener.

The integrated camera 612 may be operable to capture an image of thelistener and utilize a face recognition algorithm to determine alocation of the head of the listener. Information identifying thelocation of the head of the listener may be communicated to thecontroller 608.

The controller 608 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to control operation of the sensors S1,S2, S5, and the integrated camera 612. In this regard, the controller608 may be operable to acquire and process data from the proximitysensors S1, S5 in order to determine the height of the listener. Thecontroller 608 may also be operable to receive and process theinformation from the integrated camera 612, which identifies thelocation of the head of the listener. The controller 608 may be operableto combine the information identifying the height of the listener withthe information identifying the location of the head of the listener toget a more accurate location of the head of the listener. The controller608 may be operable to control the one or more motorized mounts in theenclosure 602 in order to optimally adjust the angle of the ultrasonicgenerators/emitters 604 a and 604 b so that they may direct and projectthe 3D hypersound audio towards the ear of the listener based on thecombined information identifying the height of the listener and theinformation identifying the location of the head of the listener. Theultrasonic generators/emitters 604 a and 604 b may then project 3Dhypersound audio from the floor up towards the head of the listener.

In some example implementations, the controller 608 may be operable tocontrol the one or more motorized mounts in the enclosure 602 in orderto optimally adjust the angle of the ultrasonic generators/emitters 604a and 604 b so that they may direct and project the 3D hypersound audiotowards the ears of the listener based on the information from theintegrated camera identifying the head and ears of the listener. Theultrasonic generators/emitters 604 a and 604 b may then project 3Dhypersound audio from the floor up towards the head and ears of thelistener.

FIG. 7 is a flow chart illustrating an example process for generatinghypersound audio from an ultrasonic emitter system floor audio unit, inaccordance with various example embodiments of the present disclosure.Shown in FIG. 7 is a sequence 700 of example steps for operating anultrasonic emitter system floor audio unit using predetermined listeningposition markers.

In step 702, the user is positioned in an optimal location whereultrasonic generators/emitters may be received by the listener. This maybe done by use of pre-determined listening position markers (e.g., theoptimal standing position marker 626).

In step 704, the ultrasonic generators/emitters project 3D hypersoundaudio from the floor up towards the head of the listener. This maycomprise making any required adjustments (e.g., to angle of ultrasonicgenerators/emitters, beamforming applied, etc.) based on thepre-determined positioning markers.

FIG. 8 is a flow chart illustrating an example process for generatinghypersound audio from an ultrasonic emitter system floor audio unit, inaccordance with various example embodiments of the present disclosure.Shown in FIG. 8 is sequence 800 of example steps for operating anultrasonic emitter system floor audio unit based on determination oflisteners' positions.

In step 802, one or more sensors (proximity, microphones, etc.) and/or acamera may be configured to acquire information which may be utilized todetermine the location of the head of a listener.

In step 804, information may be acquired from the one or more sensorsand/or camera (e.g., one or more of sensors S1, S2, S3, S4, S5, S6, andS7, and/or camera 612).

In step 806, the acquired information from the one or more sensorsand/or camera may be processed (e.g., via the controller 608).

In step 808, the location of the head of the listener may be determined(e.g., via the controller 608) based on the processed information.

In step 810, the ultrasonic generators/emitters may be adjusted (e.g.,by the controller 608, such as, for example, by controlling a movementmechanism or beamforming associated with the ultrasonicgenerators/emitters) so that they project up towards the head and earsof the listener based on the determined location of the head of thelistener.

In step 812, the ultrasonic generators/emitters project 3D hypersoundaudio from the floor up towards the head and ears of the listener,providing optimal listening experience.

FIG. 9 is a flow chart illustrating an example process for hypersoundaudio from an ultrasonic emitter system floor audio unit, in accordancewith various example embodiments of the present disclosure. Shown inFIG. 9 is a sequence 900 of example steps for example steps foroperating an ultrasonic emitter system floor audio unit based oninteractions with listeners.

In step 902, the listener may be detected when the listener is within aparticular proximity of the ultrasonic emitter system floor audio unitmay be detected. The detection may be performed using suitable sensors(proximity, microphones, etc.), cameras, etc., which may be configuredto detect listeners when in particular proximity of the ultrasonicemitter system floor audio unit.

In step 904, an audio prompt may be generated and/or played, instructingthe listener to stand in a particular location.

In step 906, an audio prompt may be generated and/or played, instructingthe listener to speak.

In step 908, the location of the head of the listener may be determined(e.g., via the controller 608) based on the source of the listener'svoice utilizing one or more directional microphones.

In step 910, the ultrasonic generators/emitters may be adjusted (e.g.,by the controller 608, such as, for example, by controlling a movementmechanism or beamforming associated with the ultrasonicgenerators/emitters) so that they project up towards the head and earsof the listener based on the determined location of the head of thelistener.

In step 912, the ultrasonic generators/emitters project 3D hypersoundaudio from the floor up towards the head and ears of the listener.

Other embodiments of the disclosure may provide a non-transitorycomputer readable medium and/or storage medium, and/or a non-transitorymachine readable medium and/or storage medium, having stored thereon, amachine code and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein.

Accordingly, the present disclosure may be realized in hardware,software, or a combination of hardware and software. The presentdisclosure may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different units arespread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present disclosure may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present disclosure makes reference to certain embodiments, itwill be understood by those skilled in the art that various changes maybe made and equivalents may be substituted without departing from thescope of the present disclosure. In addition, many modifications may bemade to adapt a particular situation or material to the teachings of thepresent disclosure without departing from its scope. Therefore, it isintended that the present disclosure not be limited to the particularembodiment disclosed, but that the present disclosure will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method, comprising: in a floor audio unit that comprises one or more ultrasonic emitters, the floor audio unit being placed on or near a floor: generating audio output that comprises ultrasonic signals; and emitting the ultrasonic signals using the one or more ultrasonic emitters, wherein: the one or more ultrasonic emitters are configured to emit the ultrasonic signals upward; and the directionality of emission of the ultrasonic signals is based on a position of a listener and/or a location of the listener's head relative to the floor audio unit.
 2. The method of claim 1, comprising adjusting positioning of the one or more ultrasonic emitters based on the position of the listener and/or the location of listener's head to optimize the directionality of emission of the ultrasonic signals.
 3. The method of claim 1, comprising configuring the ultrasonic signals and the emission of the ultrasonic signals via the ultrasonic signals to create a particular audio experience by the listener.
 4. The method of claim 3, wherein the particular audio experience by the listener comprises three-dimensional (3D) hypersound.
 5. The method of claim 1, comprising determining the position of the listener and/or the location of the listener's head.
 6. The method of claim 5, comprising determining the position of the listener and/or the location of the listener's head based on sensory data obtained from one or more sensors.
 7. The method of claim 5, comprising determining the position of the listener and/or the location of the listener's head based on visual data obtained via a camera.
 8. The method of claim 5, comprising determining the position of the listener and/or the location of the listener's head based on audio input provided by the listener, and captured via one or more microphones.
 9. The method of claim 8, comprising processing the audio input to estimate the position of the listener and/or the location of listener's head relative to the floor audio unit.
 10. A system, comprising: a floor audio unit that comprises one or more ultrasonic emitters, the floor audio unit being placed on or near a floor during operation, the floor audio unit being operable to: generate audio output that comprises ultrasonic signals; and emit the ultrasonic signals using the one or more ultrasonic emitters, wherein: the one or more ultrasonic emitters are configured to emit the ultrasonic signals upward; and the directionality of emission of the ultrasonic signals is based on a position of a listener and/or a location of the listener's head relative to the floor audio unit.
 11. The system of claim 10, wherein the floor audio unit is operable to adjust positioning involving the one or more ultrasonic emitters based on the position of the listener and/or the location of the listener's head to optimize the directionality of emission of the ultrasonic signals.
 12. The system of claim 10, wherein the floor audio unit is operable to configure the ultrasonic signals and the emission of the ultrasonic signals via the ultrasonic signals to create a particular audio experience by the listener.
 13. The system of claim 12, wherein the particular audio experience by the listener comprises three-dimensional (3D) hypersound.
 14. The system of claim 10, wherein the floor audio unit is operable to determine the position of the listener and/or the location of the listener's head.
 15. The system of claim 14, wherein the floor audio unit is operable to determine the position of the listener and/or the location of the listener's head based on sensory data obtained from one or more sensors.
 16. The system of claim 14, wherein the floor audio unit is operable to determine the position of the listener and/or the location of the listener's head based on visual data obtained via a camera.
 17. The system of claim 14, wherein the floor audio unit is operable to determine the position of the listener and/or the location of the listener's head based on audio input provided by the listener, and captured via one or more microphones.
 18. The system of claim 17, wherein the floor audio unit is operable to process the audio input to estimate the position of the listener and/or the location of listener's head relative to the floor audio unit.
 19. A floor audio system, comprising: an enclosure that is configured for placement on or near floors; one or more ultrasonic emitters within the enclosure; and one or more circuits that are operable to: generate audio output that comprises ultrasonic signals; and emit the ultrasonic signals using the one or more ultrasonic emitters, wherein: the one or more ultrasonic emitters are configured to emit the ultrasonic signals upward; and the directionality of emission of the ultrasonic signals is based on a position of a listener and/or a location of the listener's head relative to the enclosure of the floor audio system.
 20. The floor audio system of claim 19, wherein the one or more circuits are operable to adjust positioning of the one or more ultrasonic emitters based on the position of the listener and/or the location of the listener's head to optimize the directionality of emission of the ultrasonic signals.
 21. The floor audio system of claim 19, wherein the one or more circuits are operable to configure the ultrasonic signals and the emission of the ultrasonic signals via the ultrasonic signals to create a particular audio experience by the listener.
 22. The floor audio system of claim 21, wherein the particular audio experience by the listener comprises three-dimensional (3D) hypersound.
 23. The floor audio system of claim 19, wherein the one or more circuits are operable to determine the position of the listener and/or the location of the listener's head.
 24. The floor audio system of claim 19, comprising one or more sensors for obtaining sensory information relating to the listener, the sensory information being used to determine the location of the listener and/or the location of the listener's head.
 25. The floor audio system of claim 24, wherein the one or more sensors comprise proximity sensors, audio input devices, and/or cameras.
 26. The floor audio system of claim 24, wherein the sensory information is used in determining the location of the listener and/or the location of the listener's head.
 27. The floor audio system of claim 24, wherein: the sensory information comprises an audio input provided by the listener and captured via the one or more sensors; and the one or more circuits are operable to process the audio input to estimate the position of the listener and/or the location of listener's head relative to the enclosure. 